Dispersions of titanium dioxide in various liquid carriers are used by cosmetic chemists for UV protection in sunscreen products and in daily wear cosmetics such as foundations and moisturizers. These systems typically use special chemicals to help fully disperse the titanium dioxide in the carrier, and to keep the dispersion viscosity as low as possible so higher levels of the powder can be incorporated. These special chemicals are called “dispersing agents” or “wetting agents” and typically include polyhydroxystearate, or Isopropyl titanium triisostearate. One disadvantage of adding these additional chemicals to the dispersion is that their presence could affect the eventual stability of the finished sunscreen formula by interfering with the delicately balanced emulsifier system, as they are usually surface-active compounds themselves. Since the majority of consumer sunscreen products are emulsion-based, and potential instability may take up to several months to present itself, this can cause time delays during the formulation screening process. Also, the addition of a wetting agent to a dispersion has typically been necessary to achieve both a high concentration of titanium dioxide and a low dispersion viscosity; the high concentration being advantageous due to minimized shipping costs of the raw material, and the low dispersion viscosity being advantageous due to the formulating flexibility it offers.
Sunscreen technology has been changing recently to keep up with consumer preferences. Ease of sunscreen application is becoming increasingly important to consumers, as is evidenced by the increased number of sunscreen spray-on products introduced to the market. In order to design these products to spray properly, a low formulation viscosity is preferable. In addition, consumers are becoming more aware of the safety of the ingredients used in their cosmetic products. In particular, the use of silicone and silicone-based products has drawn negative attention from the media. Silicone and its derivatives have been used as the primary carrier, wetting agent or coating agent in a number of commercially available sunscreen dispersions that formulators have come to depend on. However, silicone and its derivatives, though widely used in cosmetics for many years, are once again undergoing scrutiny for their safety as well as environmental impact. In view of this situation, silicone and its derivatives may fall out of favor with consumers, requiring formulators to find suitable substitutes if they are to continue providing dispersion-based sunscreen products. Thus there is a need for silicone-free, aesthetically pleasing carriers that can contain large amounts of particulate sunscreens without building inordinate amounts of viscosity, without wetting agents and coatings on the titanium dioxide that contain silicone derivates.